October 2012 Archives

Dear AntBlog:

I am Eva Rogge, R&D Engineer at Europlasma, located in Belgium, Europe. We are specialized in nanocoatings, for example to provide water repellent and oil repellent properties to a material. Our coatings can be applied on all kinds of materials: textiles, plastics, electronics.

I have been contacted by a person who makes electronic apparatus used outdoors. He has noticed that ants are attracted by the electromagnetic fields. They come into the apparatus, live there, and produce excreta. Because of these excreta, short circuiting of the devices occur.

The idea is now to apply a nanocoating on these electronic components to protect them against the excreta of ants. To investigate if this is achievable, I was wondering if you have any idea of the main components of the feces of ants.

Kind Regards, Eva
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Dear Eva:

Ant "feces" is not feces in the same sense as for us mammals. The diet of adult ants is mainly liquid, containing only the tiniest solid particles, so there is only a small component of indigestible solids. Further, the insect equivalent of kidneys, called Malpighian tubules, empty into the rectum rather than into a separate bladder as in our species, so the nitrogenous waste or urine, in the form of uric acid crystals suspended in a fluid that is mainly water, is mixed with the feces. This results in a light brown (café au lait color, if you will), thick suspension of mixed waste, excreted as droplets through the cloaca (anus) at the tip of the ant's abdomen. In sum, I would say that the general description of the ant excreta is a suspension composed primarily of uric acid crystals and very small particles of insoluble carbohydrates (cellulose, chitin) and cuticular (exoskeleton) proteins in a polar liquid.

In nature, ants typically use latrine areas for the deposition of this waste, apart from where they feed and rest and rear their brood. An internet search will reveal that there is a fair bit of literature on ants infesting electrical circuitry, but this is mostly unsatisfying, in that the studies do not really elucidate either why the ants accumulate on electrical circuitry, or why they soil the premises while there.

Finally, I would suggest that it would be good for you to team up with an analytical chemist, so that more precise details of the chemistry of ant excreta could be determined.

Regards,
James C. Trager & the Ask Ant Team

Dear Ant Experts,

I have a large colony of ants in my yard (or possibly many colonies) in Surprise, AZ. These ants are becoming a small problem because they love to bite my family. So far I have tried many "ant baits" and found that they ignore all of them except for amdro pellets which contain Hydramethylnon. Boiling water works great on them when I can locate their hills, but they always return. Any information on what kind of ants these are and how to eradicate them will be very appreciated! Thank you in advance!

-JJ
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Dear JJ,

I wish I had some encouraging news for you, but it's likely you have Solenopsis xyloni, a close relative of the Red Imported Fire Ant, Solenopsis invicta. You're already doing some of the most effective things: Amdro was developed specifically to target S. invicta (or RIFA, as it's sometimes called in the invasive species literature). It works best if you pour about 1/4 cup directly onto the mounds, and re-treat every 2-3 weeks. In general, poisoned baits usually kill at most about 90% of the colony, so re-treatment is essential. Boiling water, as you said, is also great when you can find the colonies. Just don't pour it over the Amdro! It doesn't work when wet!

The problem is, unless you and your family live on a 1,000-acre ranch, miles away from town, surrounded by a moat and a flying-ant-proof fence, you'll always risk re-infestation from the surrounding area. Therefore, the only further advice I have is to get organized with your community. It might make sense to bring this problem up with your neighbors, at your children's schools, and any local organizations you're involved with. The "School of Ants" is a citizen-science project that would be a fantastic way to gather information about where other colonies of these ants occur in your area...and the students might even learn a thing or two about the biology and ecology of ants!

One critical bit of information you can get from collaborating with the folks at "School of Ants," or other experts, is a positive identification of these specimens. Solenopsis invicta and Solenopsis xyloni are difficult to tell apart from pictures, but one is a native ant that can be a nuisance, and one is an invasive ant that costs the USA more six billion dollars a year to control nation-wide. More information on Solenopsis invicta, and some advice about distinguishing it from related species, can be found on this excellent site.
Either way, you have the opportunity to raise awareness in your community about ants, so that you can more effectively solve the problem you have now, and be prepared for future ant invasions.

Good luck!
Jesse Czekanski-Moir & the AntAsk Team

I'm not an ant observer, but I recently noticed ants on my sidewalk behaving in a manner I hadn't seen before.

The sidewalk is shaded by an oak tree that is dropping thousands of tiny, hard cone-like kernels about 1/8" long and slightly less in diameter. Simultaneously this tree also drops mature acorns, so I don't know whether the tiny cones are related to the acorn process or not. The ants are also very small - 1/8" or less long.

About a week ago, I noticed occasional tightly gathered 'circles' of cones - usually about 1-1/2" to 2" in diameter, and about one to three or four cones in height. Upon further examination we discovered the circles were being 'built' by the ants, and also discovered that these 'circles' were being built around dead or dying caterpillars. Some ants were continuing to build the pile - while a steady stream of others were going back and forth - presumably carrying bits of the caterpillar back to the nest. After the ants abandon the pile, there is nothing left of the caterpillar.

I suspect this is not an unusual ant activity, but since I know little about ant behavior, I'm curious about the reason for the temporary burial of the caterpillar. Are they hiding or protecting their food-source from other predators - restricting the movement of a still living caterpillar - or what?

Here are a couple of photos - the first showing the cones as they distribute when they fall, and the second shows a caterpillar in the process of being surrounded and covered.

Thanks for your help.

Dave Owen
Lakeland, FL

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Dear Dave,

As you live in Florida, we reached out to a Florida ant expert, Lloyd Davis, and here is what he had to say:

"About this ant behavior: First, the "cones" are caterpillar dung. I suspect from the color of the ants on the caterpillar that the ants are imported fire ants. I have seen fire ants bring dirt onto a glue trap to gain access to food trapped in the glue. This however looks too far fetched. Unless someone watched the process and saw the ants positioning the caterpillar dung, I suspect some other reason for their arrangement and that it is just a coincidence that the ants are feeding on the caterpillar in the middle of the pile."

In the insect world, we often call insect "dung" or waste by the name frass. This may explain why the frass is accumulating near the caterpillar as this is the source.

Red imported fire ants (Solenopsis invicta) are unfortunately common in Florida. You can see photos of them here and here.

To learn more about red imported fire ants you can read some of our previous posts including here and here.

Thank you for contacting AntBlog,
Corrie Moreau & the AntAsk Team

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UPDATE:

Hi Corrie -

Thank you for pursuing an answer to my 'ant' question and notifying me of Mr. Davis on-line response; however I'm still puzzled by a number of points that likely have been explained had I been more thorough in my question.

If the 'cones' are, as Mr. Davis says, caterpillar frass, I am astounded by the quantity, distribution, size and shape uniformity (they look very much like sub-miniature pine cones or a tiny shelled ear of corn). When I spoke of 'thousands' of the little 'cones', it was not an exaggeration. Although no longer happening, when it was the entire portion of the sidewalk beneath the oak tree (roughly 160 sf) would be littered with these 'cones' within 24 hours after the sidewalk was swept. Incidentally, the appearance of the 'cones' started about two weeks before I wrote, and stopped almost totally and suddenly a few days after my previous note. Except when there was a 'circle', the distribution of the cones was almost uniform over the entire sidewalk area beneath the tree - and oddly there never any on the sidewalk beyond the foliage of the oak tree.

I should have noted that I did personally see the ants constructing these 'circles', and there was always a dead caterpillar or other insect in the middle. It was amusing to see these tiny ants (perhaps 1/16" in length is more accurate than 'smaller than 1/8"') swinging the 'larger-than-themselves' cones to and fro as they carried them to the pile. As the 'cone-circles' grew, the cones around the pile almost totally disappeared, defining an increasingly larger 'empty' circle largely devoid of cones (the 'cleared' circles got as large as 6" in diameter from the pile center).

I'm very familiar with imported 'fire ants', and the 'circle-builders' may well be that type, although they seem smaller and darker in color than the many other colonies we constantly battle on our large lot. These ants are almost black in color - with just a hint of red, and both front and back seem to be rounded - rather than 'wasp-shaped'. The fire ants we have in our yard all have piles of excavated sand around them that continue to grow until we poison them. The small ants about which I wrote seem to live beneath the sidewalk, and I've not seen any excavated dirt or sand, although I know it must be there.

Neither my sister nor I have ever noticed this phenomenon before in the many years we have lived here. If it does happen again, I'll try to get more information and a close-up photo of an ant moving one of the cones.

Again, I want to thank you and Mr. Davis for responding to my inquiry.

Dave
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Dave,

Regarding your second inquiry, here is what another ant expert, James Trager, had to say:

"I agree that the "cones" are caterpillar frass, and from their size, would even go as far as to suggest that they were produced by some sort of oak-feeding saturniid. Leaves are not an especially nutritious food, especially tannin-filled oak foliage, so caterpillars have to eat prodigious amounts to fuel their rapid growth rates, from tiny egg to several-inch long caterpillar in just a couple of weeks or so. This explains the rapid appearance and disappearance of the frass, and why all the frass was under the drip-line of the tree. .

Fire ants almost invariably bury large items for butchering. It doesn't surprise me that, in the absence of convenient soil particle, sawdust, or what-have-you, the ants used caterpillar frass for their burying ritual. The smaller, darker description of the ants also fits for a "butchering party" of fire ants. These gatherings usually comprise mostly or only the smaller workers, which are more uniformly dark colored."

I hope this helps!

All the best,
Corrie Moreau, James Trager, & the AntAsk Team

Wow! I didn't even know your organization existed and happened upon it by accident. Anyway, while in Namibia last spring (2012) I came upon this interesting ant while in the red dunes of Sossussvlei, Namibia. I tried to identify it when I got home, but with no luck. Can you help?

Thanks very much,

Brandi

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Dear Brandi,

Thanks for your fantastic images!

The ants pictured are Camponotus detritus, otherwise known as the Namib Desert dune ant. This species is noteworthy not only for its striking appearance, but also its peculiar adaptation to the extreme aridity of the Namib Desert. You can read more about their distribution, behaviour, and unique physiology here.

Thanks for your interest!

Alexandra Westrich & the AntAsk Team

Hi!

I am Natalie, I'm in 8th grade in chicago and i Am doing science fair, I am putting ibuprofen in ants food and drink. My question is: Will trace amounts of ibuprofen affect the behavioral patterns of red harvester ants? I have both on my ant farms set up, and 15 ants in each, I just would like some help along the way so i can do a great science fair!

Thanks and hope to hear from you soon.
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Dear Natalie,

We are glad to hear that you are participating in a science fair and that you are planning to include ants in your experiment. Regarding the experiment you are planning to conduct, here are a few things to consider:

- How will you measure the behavioral patterns of the ants to see if they are different? There are many ways to do this, but you will want to come up with some way to standardize your measurements. Will it be how much food they consume and how will you determine this? How often the ants are active versus not moving for specific periods of time that you are watching them? How often do the ants engage in different behaviors between the treatments (grooming themselves, grooming other ants, etc.)? There are lots of observations you could make, just be sure to decide ahead of time what you will do. One idea might be to just spend some time watching your ants before starting the experiments to get ideas.
- To insure that you are measuring the effect of the ibuprofen, you will need to have a "control", which in your case would be a group of ants that you are not feeding ibuprofen, but otherwise are treated and fed exactly the same. This will allow you to determine if the ibuprofen is what is causing the differences.
- You would ideally also like to have multiple pairs of ants that are and are not fed ibuprofen (but I realize this may not be possible for your project this year).

We hope this helps and have fun watching your harvester ants! Harvester ants from the genus Pogonomyrmex are beautiful animals (to see what they look like up close click here).

Enjoy,
Corrie Moreau & the AntAsk Team

Hi -- I was visiting Guarulhos in Brazil recently, and I found these ants in a tree or bush interacting with other insects. I suppose they are Camponotus atriceps or Camponotus mus and the insects probably a kind of cicada. I have to send the picture to a outdoor photography magazine and I need the Latin name, at least the genus. The picture was taken at the gardens of the Cesar Palace Hotel near to the international airport. One of the photos is of what looks like to be the nest. Can you get to me information about the other insect or the plant?

Thanks.

Javier Castosa, Madrid, Spain

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Dear Javier:

First, the bad news. I am sorry to say I cannot identify the plant in the pictures.

On the other hand, from the perspective of the AskAnt Team, you are really fortunate to have traveled to Brazil, one of the most ant-rich places in the world, where even an urban hotel garden can reveal fascinating aspects of ant behavior. The ants in your pictures are a species common both in the wild savannas and in gardens of that part of Brazil, namely Camponotus rufipes. (C. atriceps is a litttle smaller, and much shinier, and C. mus is considerably smaller with whiter hairs). When their nest is disturbed, C. rufipes can be very aggressive, delivering a strong bite into which they may squirt caustic formic acid. I had one draw blood from my finger one time, when I was doing field work in Brazil! It is one of the few ants that can do this.

The ants in your lovely pictures are associated with two types of sap-feeding insects, scale insects (round and featureless, Hemiptera: Coccidae) and planthoppers (colorful and cicada-like, Hemiptera: Fulgoroidea). Both of these animals excrete excess sugar and water from their plant sap diet in the form of honeydew (melaza in Spanish). Like many ants, C. rufipes is fond of sugar, and lingers around the honeydew "factory" to gather this waste product as it is produced by the sap-feeding bugs. you could say that one insect's garbage is another insect's treasure! The honeydew bugs in this relationship are sometimes referred to as ant-cattle. The ants also defend the bugs from parasites, predators, and competing ants.

This ant is known to make a nest of cut grass, a picture of which can be seen at the link in the next paragraph. Out in the savanna, this ant may nest in low, wet areas, and its nests may be suspended among grass stalks above the saturated ground, looking something like birds' nests. As your second picture shows, the ants also use bits of grass to build structures covering their "cattle", an additional way to shelter them from enemies. Partly chewed and glued-together plant fibers used by ants for construction are referred to as carton.

Here's a post about C. rufipes at one of our favorite blogs: http://myrmecos.net/2012/06/13/answer-to-the-monday-night-mystery-camponotus-rufipes/. Another post at the myrmecos blog lists this ant as the 48th most published ant species (among over 12,000 species to choose from). Your intention to publish these photos in an outdoor magazine will make them just a little bit more well-published.

James C. Trager & the AskAnt Team



Thanks for your question, Nathalie!

It is true that ants are proportionately much stronger than we are. I don't think any human could dangle from the ceiling with 100 times his or her body weight, like the weaver ant Oecophylla pictured here. There are many adaptations that are working together to allow ants to perform impressive feats like these: hairs on their feet that can stick to very smooth surfaces, large muscles in their heads to close their jaws, and light lean bodies. Most worker ants don't have functional reproductive systems, so their strength-to-weight ratios are higher than many other insects that are weighed down with the burden of perpetuating their genes.

However, comparing the proportional strength of even the strongest humans to an ant is unfair. Even lions, tigers, and bears (oh my!) can't lift more than 10 times their own body weight, as many insects can. Some of the physics behind this is explained here. The strength of ants is "super," but it is not super-natural. It all makes sense once you know a little more about physics.

Briefly, smaller organisms will always have bigger strength-to-weight ratios, because it's the surface area of the muscle cross section that determines strength, but the volume of the animal that (all else being equal) determines mass.

Less briefly: imagine three perfect cubes, each of a different length: 2cm, 5cm, and 10cm. The 2cm cube has a cross-sectional area of 2x2=4cm^2 and a volume of 2x2x2=8cm^3. The 5cm cube has a cross-sectional area of 5x5=25, and volume of 5x5x5=125, and the 10cm cube has cross-sectional area of 10x10=100 and 10x10x10=1000. If these cubes were animals (admittedly, very strange ones), the 2cm cube could have a strength-to-weight ratio that was proportional to 4/8, while the 5cm animal's strength to weight ratio would be 25/125 = 1/5, and the largest, 10cm cube-animal would have a strength-to-weight ratio of 10/1000 = 1/100. Of course, this is an oversimplification, but I hope this helps clarify why all of the proportionately strongest animals are very small.

Although this is an ant blog, I feel it is only fair to point out that ants are not the strongest insect, even proportionately to their body weight. The prize goes to a dung beetle, which can drag more than 1000 times its body weight. These beetles are larger than any ant, which makes their strength-to-weight ratio even more impressive.

The feat of strength in which ants have beetles beat is how rapidly some of them can close their jaws. Ants of the genus Odontomachus can close their jaws at speeds of up to 230 km/hr (143mph), generating a force that is 500 times their body mass. Not only are these forces very effective at subduing prey and smaller enemies, some of them can use their jaws to launch themselves into the air. This youtube video is completely worth checking out if you like wathching slow-motion ants flail through the air. For a more dignified synopsis, one of the original articles on Odontomachus jaws is here.

I hope this helps!
best,
Jesse Czekanski-Moir & the AntAsk Team